Drill.



W. S. PEIRC.

DRILL.

APPucmoN man SEPT. n. |913.

Patented ont. 29, 1918.

. WIM. 515,1.zxel AQ RALPH S. PEIRCE, 0F HINSDALE, ILLINOXS.

DRILL.

Lacasse.

Specification of Letters Patent.

Patented Uct. 29, lglld.

Application led September 17, 1913. Serial No. 790,310.

To all whom 'it 'may concern.'

Be it known that I, RALPH S. Piemon, citizen of the United States,residing at Hinsdale, in the county of Dupage and State of Illinois,have invented a certain new and useful Improvement in Drills, of whichthe following is a full, clear, concise, and exact description,reference being had to the vaccompanying drawings, forming a part ofthis specification.

My invention relates to drills and finds a useful embodiment in handoperated percussion drills, though the invention is not to be limited toan embodiment in hand operated drills nor percussion drills.

The invention has for one of its objects the provision of a drill whosemechanism will preferably effect forced passage of' air through or alongthe tool into the hole being drilled to eject the dust resulting fromthe drilling, though the invention is not to be limited to the meansemployed for forcing the air. Another object of the invention is toprovide, in a percussion drill, a spring through the intermediation ofwhich the drill point is raised or withdrawn preparatory to a freshblow. There is also a spring to aid in the hammer recoil.

My invention has other characteristics and will be explained fully byreference to the accompanying drawing showing the preferred embodimentthereof and in which Figure 1 is a sectional view; Fig. 2 is a view inelevation of a modification; Fig. 3 is a sectional view on line 3 3 ofFig. 1; and Fig. .tis a view, on a larger scale, of a part of thestructure shown in Fig. 2 on line 4 4. f Like parts are indicated bysimilar charriicters of reference throughout the different res. g'llhedrilling tool 1 is held within the bore of a tool stock 2 by anysuitable fastening device, such as a clamping screw 3. The tool stockhas a head 4 at its upper end to receive the blows of a. hammer 5, thestock being gripped by one hand and the hammer by the other. The stockis provided with a stem 6 in tight connection therewith and thatprojectsupwardly therefrom and one of its purposes is to uide thehammer, which has a lon 'tudinal ore freely receiving said stem, as 1tis driven toward the stock and as it is Withdrawn. The uglper end of thestem 6 is enlarged into a ead by means of a cap 7 screwed thereon. Acushion preferably inthe form of a coiled spring 8 is disposed withinthe bore of the hammer 5 an about the stem 6 projecting from the stockinto or along the hammers, this spring being of such diameter as toenable it to be compressed when engaged by the head 7 with suiiicientforce. The bore of the hammer 5 is contracted at its lower end to adorda seat for the lower end of the spring.

The hammer surrounds the stem and strikes the stock head 4 whereby thestock is struck laterally of the stem to relieve the stem of directhammer blows and avoid tendency of such blows to buckle the stem. Thespring 8 acts as a cushion between the stem cap 7 and the hammer andthrough which the hammer, when lifted, operates to withdraw the tool,this spring receiving none of the hammer blows.

After the hammer blow has been struck, the hammer is moved upwardly withrespect to the tool, to permit the spring 8 to press,

upon the head 7 with the necessary force upon said head to effect theslight partial withdrawal of the stock. In the form shown in Fig. 1, aspring cushion 8 may be interposed between the hammer and the toolstock. This spring is placed under compression during the progress ofthe hammer into engagement with the stock and aids in the recoil of thehammer. The device is one with which light blows are to be rapidlystruck, the springs obviously aiding in this result. Upon each partialor slight withdrawal ofthe tool it may be slightly turned upon thedepression of a plunger 9 to present the tool to a new portion of thework, this plunger having teeth upon its inner end for engaging helicalgrooves 10 upon the stem 6.

Hitherto the stem 6 and tool stock 2 were held together by a pintransversely passing through the stem and the stock, such pin weakeningthe stock and stem and bemg subject to shearing strain. These defectsare overcome by enlarging the lower end of the stem to form a shoulder11 that engages a corresponding shoulder within the -bore of the stock.The stem thus operates directly upon the stock to effect withdrawal ofthe tool, and the major part of the force of the hammer blows may bedirectly transmitted from the Stock to the enlarged lower end of thestem and through this lower stem and to the tool 1 in abuttingengagement with the stem, this construction enabling me to dispense withthe coupling pin and t0 VOd the harmful results attendant upon the usethereof.

Alined air channels 12, and 13 are formed in the tool 1 and stem 6,through which air is forced downwardly for the purpose of dislodging thedust in the hole, the channel 13 extendmg tothe working end of the tool.The means preferably employed for thus forcing the air resides in themechanism of the device itself, for which purpose the head 7' has closesliding lit with the portion of the bore containing spring 8 then to actas an air pump piston, while the upper end of the hammer is providedwith a ball valve 14 which closes the passage 15 leading from the hammerbore to the external air when the hammer is driven toward the tool,whereby air is jetted through the composite air passage 12, 13 duringthe movement of the hammer toward the stock to blow the dust away frombeneath the tool preparatory to the operation the tool is to performwhen the hammer strikes. VVhenthe hammer is raised the valve will`unclose to permit air to enter the hammer interior by way of thepassage 15. I do not limit myself to the formation of the air passage12, 13 within the tool and Stock Stem. The spring 81 also maintains thehammer or impacting element 5 and the tool structure l, 2, f1 slightlyapart, when the tool is not in use, so that upon the initial movement ofthe hammer and during the time spring 81 is compressed the hammer causesa puff of air to flow through the passage 13 to the lower end of thetool. A

While I have herein shown and particularly described the preferredembodiment of my invention I do not wish to be limited to the precisedetails of construction shown as changes may readily be made without dearting from the spirit of my invention. aving thus described myinvention I claim as new and desire to secure by Letters Patent thefollowing 1. A percussion drill including a too] carrying stock; ahollow hammer arranged to strike the stock to drive the tool; a stemprojecting from the stock into the hammer interior, and having an airchannel affording communication between the hammer interior and thedrilling end of the tool whereby air displaced by the stem within thehammer interior may be directed to the drilling end of the tool; and avalve operated by the air displaced from thehammerv interior to close avalve passage which is provided between the hammer interior and theexternal air.

2. A percussion drill including a tool car-- rying stock; a hollowhammer arranged to strike the stock to drive-the tool; and a stemprojecting from the stock into the hammer interior and having an air'channel affording communication between the ham mer interior and thedrilling end of the tool whereby air displaced by the stem within thehammer interior may be directed to the drilling end of the tool, therebeing a valve passage for permitting the entry of air within the hammerinterior when the hammer is withdrawn from the tool.

3. A percussion drill including a tool can rying stock; a hollow hammerarranged to strike the stock to drive the tool; and a stem projectingfrom the stock into the hammer interior and having an air channelaffording communication between the hammer interior and the drilling endof the tool whereby air displaced by 'the' stem within the hammerinterior may be directed to the drilling end of the tool.

4. A hollow impacting element in combination with a drill structurehaving a portion entering the hollow of the impacting element andprovided with an airchannel extending to the working end of the toolstructure .and communicating withthe interior of the impacting elementwhereby the impacting element, in striking movement, forces air throughsaid channel to the working end of the tool.

5. A hollow impacting element in combination with a drill structurehaving a portion entering the hollow of the impacting element andprovided with an air channel extending to the working end of the toolstructure and communicating with the interior of the impacting elementwhereby the impacting element, in striking movement, forces air throughsaid channel to the working end of the tool; and a spring for normallyspacing the engaging parts of the hammer and drill structure apart.

In witness whereof, I hereunto subscribe my name this twenty ninth dayof July A. D., 1913.

RALPH S. PEIRCE.

Witnesses:

` G. L. CRAGG,

C. L. PEIROE.

